Valves Traditional Cache
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Difficulty:
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Terrain:
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Size: 
(small)
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A bit of engineering history a short but muddy walk from the nearest road.
Thirlmere Aqueduct is the longest aqueduct in Britain, and has a maximum capacity of 227 million litres per day. When first commissioned in 1894, it ran 153km to transport water from Lake Thirlmere to reservoirs at Prestwich, some 6km northwest of Manchester. For some 22.5km of its length, the water in the aqueduct runs in tunnels, for 58km it runs through cut-and-cover constructed sections, and for 72.5km it runs through cast iron pipes. A second pipeline was completed in 1904, a third in 1915, and a fourth in 1927. The first three pipelines are in cast iron and the fourth, which terminates at Lostock Pumping Station, is made of welded steel. Each pipeline was equipped at its inlet with an equilibrium float valve that responded automatically to minor flow changes but tripped shut in the event of a high flow, such as you would get if a pipe burst. Most of these valves had to be modified in the 1940s to accommodate the installation of temporary axial flow pumps. These increased the aqueduct's capacity, which was needed pending the completion of the Haweswater Aqueduct.Some intermediate pipeline valves were also designed for automatic closing in the event of bursts — a moving paddle triggering off a pneumatic servo system to close what may have been the forerunners of present-day tilting disc valves.
There are four valves in the fields either side of the cache. They were made by Blakeborough & Sons Ltd of Brighouse.
Joseph Blakeborough established his valve-making business in Brighouse in 1878. The Blakeborough concern appears to have been very succesful, the factory remaining in use for over a hundred years. During the war the firm continued to make valves, and in the late 1940s embarked on a serious export drive. The firm closed in 1989, and the rights to manufacture parts of the product range were acquired by other firms. GA Valves still makes 'Blakeborough' parts in Brighouse.
Additional Hints
(Decrypt)
vafvqr gur onfr bs n gerr